Right, so let’s finish this one quickly.
For many years now I have seen the Muslim community especially that in India disputing among themselves over this issue, calling each other names, labeling them with some sect’s label and what not.
When it comes to the issue of taraweeh you should look at the following hadith from Sahih Bukhari as a base:
“Ibn `Umar said, "While the Prophet (ﷺ) was on the pulpit, a man asked him how to offer the night prayers. He replied, 'Pray two rak`at at a time and then two and then two and so on, and if you are afraid of the dawn (the approach of the time of the Fajr prayer) pray one rak`a and that will be the witr for all the rak`at which you have offered." Ibn `Umar said, "The last rak`at of the night prayer should be odd, for the Prophet (ﷺ) ordered it to be so.”
Now this is the base, from this the conclusion is derived that the Taraweeh or night prayer can of any length.
So the short answer is yes both are correct, the following text will only elaborate as to why.
After we have got the basics we now look into the life and practice of Our prophet (saw).
Hazrat Aisha (Ra) narrates in a Hadith in Sahih al bukhari that she had seen the Prophet (saw) pray 11 rakats in the night prayer i,e 8+3(witr).
So where did the practice of praying 20 rakats arise.
As far as I have looked this emerged at the time of Umar (Ra) who was the second Khalifa.
At his time the people prayed the taraweeh or night prayer alone in the Prophet’s mosque, someone was praying 8 over there while someone was praying 18 somewhere else.
Umar (Ra) at that time decided that the people should pray united under one Imam, so he gathered everyone around and they all prayed 20 Raka’aats of taraweeh then witr (source Al-Bukhaari (2010). As we know in Islam the teachings of the pious predecessors especially the Rashidun Khalifas are to be treated with utmost respect, and hence the 20 rakats.
So I guess things are cleared up here and Allah knows best.